During the last several years we have developed two novel, unconventional vaccine strategies generating powerful mucosal immunity to SIV antigens. The two vaccine strategies are based on human papilloma virus delivering SIV-cDNAs, designated HPV-SIV, and on HEK293-cells secreting immunogenic chaperone-gp96- Ig-SIV-peptide-complexes, designated gp96-lg-SIV. The vaccines are administered by different routes and generate mucosal immune responses by different molecular and cellular mechanisms. Different molecular mechanisms imply activation of different transcriptional and signaling pathways and may generate different degrees of protection against vaginal SIV challenge. Correlating the pathways activated by the two vaccines with immune response to SIV challenge and protection from disease will provide the information how best to combine the two vaccine strategies, if necessary, for effective protection from SIV disease. Hypothesis 1: Mucosal immunity generated by HPV-SIV and gp96-lg SIV activate different molecular and cellular mechanisms which, in turn, differentially activate the various components of mucosal immunity through different transcriptional and signaling pathways. Differential immune responses in the mucosa will translate to different degrees of protection from vaginal challenge with SIV. Hypothesis 2: Combination of HPV-SIV and gp96-lg-SIV vaccination will synergize in generating mucosal immunity by combining the activation of different transcriptional and signaling pathways thereby generating comprehensive mucosal immunity with increased power to resist vaginal SIV challenge. These hypotheses will be tested in the following specific alms: 1. Vaccinate Rhesus macaques with HPV-SIV and with gp96-lg-SIV and determine the immune response, transcriptional profiles and signaling pathways in the vagina, draining lymph nodes and systemically. 2. Challenge naive and vaccinated macaques with SIV by the vaginal route and determine immune response to the virus and viral responses to immunity during the eclipse period prior to viremia. 3. Determine the effectiveness of the two vaccines singly and in combination in SIV protection SIV infection and correlate with mucus barrier function, immune responses, transcriptional and proteomic profiles. PUBLIC HEALTH RELEVANCE: This application will study two innovative SIV vaccines that are known to generate immune responses at mucosal sites including the female genital tract. Vaccine activity in the genital tract will be analyzed by genomic and proteomic analysis in addition to immunological assays and correlated with protection from vaginal SIV challenge. The combination of the two vaccines offers the potential of comprehensive immune activation in the mucosa providing enhanced resistance to SIV infection.